From patchwork Tue Apr 9 11:07:33 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wei Liu X-Patchwork-Id: 235041 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4B6052C009C for ; Tue, 9 Apr 2013 21:22:18 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935862Ab3DILWN (ORCPT ); Tue, 9 Apr 2013 07:22:13 -0400 Received: from smtp.citrix.com ([66.165.176.89]:52765 "EHLO SMTP.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933562Ab3DILWG (ORCPT ); Tue, 9 Apr 2013 07:22:06 -0400 X-IronPort-AV: E=Sophos;i="4.87,438,1363132800"; d="scan'208";a="18295987" Received: from accessns.citrite.net (HELO FTLPEX01CL03.citrite.net) ([10.9.154.239]) by FTLPIPO01.CITRIX.COM with ESMTP/TLS/AES128-SHA; 09 Apr 2013 11:22:06 +0000 Received: from ukmail1.uk.xensource.com (10.80.16.128) by smtprelay.citrix.com (10.13.107.80) with Microsoft SMTP Server id 14.2.342.3; Tue, 9 Apr 2013 07:22:05 -0400 Received: from dt47.uk.xensource.com ([10.80.229.47]) by ukmail1.uk.xensource.com with esmtp (Exim 4.69) (envelope-from ) id 1UPWOv-0004o0-AO; Tue, 09 Apr 2013 12:07:45 +0100 From: Wei Liu To: , CC: , , , , , Wei Liu Subject: [PATCH 5/7] xen-netfront: reduce gso_max_size to account for ethernet header Date: Tue, 9 Apr 2013 12:07:33 +0100 Message-ID: <1365505655-8021-6-git-send-email-wei.liu2@citrix.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1365505655-8021-1-git-send-email-wei.liu2@citrix.com> References: <1365505655-8021-1-git-send-email-wei.liu2@citrix.com> MIME-Version: 1.0 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org The maximum packet including ethernet header that can be handled by netfront / netback wire format is 65535. Reduce gso_max_size accordingly. Drop skb and print warning when skb->len > 65535. This can 1) save the effort to send malformed packet to netback, 2) help spotting misconfiguration of netfront in the future. Signed-off-by: Wei Liu --- drivers/net/xen-netfront.c | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index 1bb2e20..42ef4a8 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c @@ -547,6 +547,16 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev) unsigned int len = skb_headlen(skb); unsigned long flags; + /* If skb->len is too big for wire format, drop skb and alert + * user about misconfiguration. + */ + if (unlikely(skb->len > (typeof(tx->size))(~0))) { + net_alert_ratelimited( + "xennet: skb->len = %u, too big for wire format\n", + skb->len); + goto drop; + } + slots = DIV_ROUND_UP(offset + len, PAGE_SIZE) + xennet_count_skb_frag_slots(skb); if (unlikely(slots > MAX_SKB_FRAGS + 1)) { @@ -1058,7 +1068,7 @@ err: static int xennet_change_mtu(struct net_device *dev, int mtu) { - int max = xennet_can_sg(dev) ? 65535 - ETH_HLEN : ETH_DATA_LEN; + int max = xennet_can_sg(dev) ? 65535 - VLAN_ETH_HLEN : ETH_DATA_LEN; if (mtu > max) return -EINVAL; @@ -1362,6 +1372,8 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev) SET_ETHTOOL_OPS(netdev, &xennet_ethtool_ops); SET_NETDEV_DEV(netdev, &dev->dev); + netif_set_gso_max_size(netdev, 65535 - VLAN_ETH_HLEN); + np->netdev = netdev; netif_carrier_off(netdev);